The present invention generally relates to suspensions, head assemblies, and disk drives. More specifically, the present invention relates to methods for making impact resistance and atmospheric pressure dependency of a slider compatiable with each other.
FIG. 10 shows an example of a conventional suspension and head assembly. The head assembly includes a slider 4 attached to a flexure 3 on a gimbal side of the head assembly. A load beam 2 is bent at a load bending portion 5 and carries slider 4 and flexure 3. Load beam 2 applies a press load to slider 4 to maintain the slider at a predetermined flying height.
To increase a magnetic recording density it is important to reduce a flying height of a slider and reduce a dispersion of the flying height to a predetermined range.
The dispersion in flying height is caused by a dispersion in the press load, which is primarily dependent on a dispersion in the attachment height of the suspension and an elastic rigidity of the suspension. Specifically, the relationship between the dispersion in the press load and the dispersion of the attachment height is as follows: (Dispersion in Press Load)=(Dispersion in Height of Attachment of Suspension Relative to a Surface of the Magnetic Disk)*(Elastic Rigidity of Suspension).
To reduce the dispersion in the press load (and to reduce the dispersion in the flying height) either the dispersion in the attachment height or the elastic rigidity of the load beam must be reduced. Since it is difficult to reduce the dispersion in the attachment height during assembly of the disk apparatus, the elastic rigidity of the load beam should be reduced. However, reduction of the elastic rigidity of the suspension and increases the likelihood of premature plastic deformation of the suspension due to the repeated loading and unloading of the load arm.
Damage to the data on the disk is typically caused by a shock impact which causes the slider to hit the magnetic disk surface. In order to promote the impact resistance of the suspension and head assembly, that is, restrain the slider from moving from its flying height and hitting the surface of the magnetic disk, it has been effective to reduce the equivalent mass of the suspension assembly and increase the press load on the slider. Unfortunately, when the press load is increased the flying height dependency on atmospheric pressure is deteriorated. Moreover, reducing the equivalent mass of the suspension assembly also reduces the press load, which detrimentally effects the impact resistance of the suspension.
One head assembly that attempts to resolve the above problems is illustrated in FIG. 11. A second, dummy slider 14 which does not record or reproduce information is located on the load beam 2 distal of slider 4. A large press load is applied to slider 14 while a smaller press load is applied to the slider 4 to promote the shock resistance of the suspension. Unfortunately, the load beam 2 that applies a larger press load to the dummy slider 14 is enlarged and has an increased equivalent mass. Consequently, with such designs it has proven difficult to improve the impact resistance of the head assembly.
Further, when a magnetic disk drive positions the head assembly with a, positioning mechanism of a rotary type (rotational type or swinging type), because the dummy slider 14 is distal of slider 4, there is an interference with a disk clamp or a disk spacer when accessing an innermost data area on an inner periphery of a surface of a magnetic disk. Consequently, the innermost area of the magnetic disk cannot be used for data recording. Additionally, when second slider 14 reaches an outermost data area of the magnetic disk, slider 4 will not be positioned on the outermost data area. Therefore, the outermost data area of the magnetic disk cannot be used for data recording and the overall data area for the magnetic disk is narrowed.